1. Field of Invention
This invention relates to foot operated pedals for human powered machinery, more specifically to bicycle pedals, both clipless binding pedals where the shoe is attached to the pedal, and platform or cage type pedals, where the shoe is unattached to the pedal (unbound).
2. Prior Art
Bicycle pedals traditionally have supported the cyclist's feet on a platform which could either be an essentially large flat surface, or the edges of two transverse rails, more commonly known as cages. These pedals are most commonly used in what is called here an unbound mode, operation, or style, where the shoe is not attached to the pedal with any type of binding, clip, or strap. This allows the use of almost any type of shoe to be worn while riding the bicycle and requires a minimum of skill and encumbrance to operate the pedals. Many types of bicycle riding, including some types of racing, are also performed using unbound style pedals, where there is a significant chance the cyclist might fall off the bicycle, and/or where a high degree of handling skill and balance is required. Pedals for this type of riding have evolved to provide large shoe contacting areas and highly efficient sole gripping surfaces. In addition, the shoe contacting surfaces on some pedals are slightly curved to better fit the natural curvature of the front part of the sole, for better security from slipping and for more comfort. In certain types of riding, such as freestyle, or observed trials, the bottom side of the pedal, opposite the cyclist's foot is sometimes used to rest on a stationary object, such as a curb, log, rock, etc.
The platform pedal, especially the cage style pedal, has long been modified to provide an attachment of the cyclist's shoe to the pedal. The most common type of attachment prevalent today is still the toeclip and toestrap. The toeclip is a metal or plastic strip which extends forward from the pedal, under the toes, curving up in front of the toes, and then rearwards over the top of the cyclist's front portion of the foot. A flexible, adjustable loop, called a toestrap, connects the end of this toeclip with the body of the pedal and serves to bind the cyclist's foot to the pedal, a process generally known as “clipping in”. This toeclip and toestrap shoe retention system allows the cyclist to pull the pedal rearward through the bottom of the stroke, pull it upward through the rearward part of the pedal stroke, and finally, to push it forward through the top of the stroke, all in addition to the usual downward pushing motion, which is the only propulsive stroke possible without the shoe retention system. This results in more power output and faster speeds. For more secure retention, the rails of the cage style pedal are utilized as part of a cleated shoe retention system for cyclists wearing stiff soled cycling shoes. A transverse grooved block, known as a cleat, is attached to the shoe sole, with the groove engaging the rearward cage rail. When used with a toestrap, this allows a higher force to be transmitted to the pedal through the top and bottom of the pedal stroke, and the groove aligns the shoe to the pedal, to maintain both fore/aft positioning and rotational alignment of the shoe to the pedal.
More recently, alternate means of attaching the sole of the shoe to the pedal have become popular, the generally termed clipless pedal, so named because of the lack of a toeclip and toestrap. This system comprises a binding on the pedal body that engages a binding plate attached to the shoe sole when the cyclist steps onto the pedal, similar to a step-in ski binding. This process is also generally referred to as “clipping in”, and the binding plate is also generally referred to as a “cleat”. All subsequent references to these two terms in this application pertain to clipless bindings, unless otherwise noted. After clipping in, the cyclist's foot stays attached to the pedal until a typically sideways twisting motion disengages the cleat from the binding. Several recent types of clipless binding systems for off-road bicycle usage have been designed which feature a small cleat fully recessed into the sole of the cycling shoe which then allows walking without contact of the cleat with the ground. This allows the rubber sole of the shoe to provide better traction on the ground, reducing slippage, and eliminates the marring of floor surfaces by the cleat, which is typically made from metal. These clipless shoe binding systems featuring recessed cleats have become very popular since their introduction around 1990, and though originally developed for off-road bicycle usage, they have also become popular for road cycling as well, as all cyclists wearing cleated cycling shoes must walk in them, even if only to get on and off the bicycle.
Advantages of the newer clipless binding systems, especially those with shoe recessed cleats, include the ability to have bindings on both sides of the pedal, unlike the older cage and toeclip system. This makes it easier for the cyclist to clip in to the bindings. The cyclist does not have to spin the pedal around to find the correct side. Other types of clipless pedals having only a single binding are counterweighted so that the correct side comes up automatically, however bearing friction, grease viscosity, and seal friction, all of which can be dependent on temperature, wear, adjustment, and the presence of dirt or water, tend to make this method of pedal alignment unreliable. If the pedal spins freely enough to assure that the counterweight reliably rotates the pedal, the cyclist often “overspins” the pedal inadvertently.
Both the traditional toeclip type pedal and all of the new clipless binding type pedals do not allow safe and comfortable unbound mode usage on both sides of the pedal while wearing a shoe with a cleat designed to engage the clipless binding(s). Nagano, U.S. Pat. No. 5,003,841 (1991) shows a pedal with both shoe supporting surfaces (cages), and clipless bindings on both sides of the pedal. The binding cleats for use with this pedal are large and protrude substantially downward from the shoe sole, having the disadvantage of not being recessed into the sole of the shoe sufficiently to allow comfortable and safe walking or cycling in unbound mode. This pedal does, however, allow the bindings to be sufficiently recessed into the pedal, such that a shoe having a largely smooth or lightly treaded sole, and not having a cleat attached, may be used comfortably and safely in unbound mode.
The clipless pedals designed for shoe recessed cleats and having bindings on both sides of the pedal typically feature small shoe contacting areas that are slippery and not level or smooth. They are uncomfortable and unsafe to ride without wearing a stiff soled cycling shoe with a cleat that is clipped in to the binding. The toeclip pedal has only one toeclip on one side of the pedal, and thus the other side of the pedal can be ridden unbound style, however when this is done, the toeclip and toestrap hang underneath the pedal, close to the ground, and can be unsafe and prone to damage if the toeclip or toestrap snags or drags on the ground.
All of the clipless binding pedals, as well as the older toeclip style pedal have the inherent disadvantage of being difficult to mount and ride in many cycling situations. Clipping into these pedals requires concentration and accurate foot placement. On smooth roads at low uphill, level, or downhill grades, the cyclist can coast momentarily after an initial start and generally has enough time to perform this operation even though it is inconvenient and distracting. However, for medium to high uphill grades, or on difficult off road terrain, the cyclist must begin pedaling immediately after mounting the pedals. The cyclist typically clips into a pedal before mounting the bicycle, but then does not have time or balance to clip into the second pedal, or, if using a pedal with a single binding, to determine which side of the pedal is up, and to spin the pedal if necessary. Often the cyclist must fully come to a stop, straddle the bicycle and try to get clipped in from a standstill. This can be difficult even for an experienced racing cyclist and can result in time loss during a race. For a cyclist riding on busy streets, the distraction of trying to clip into the pedal can be dangerous by diverting the cyclist's attention to traffic, especially at intersections, where many hazards exist.
In many of the conditions where clipping into the pedals is difficult, riding while clipped in is also difficult and unsafe as well. This can include riding over rough terrain where agile body motions, including lifting a foot off a pedal, are required to keep balanced over the bicycle, or when riding in busy traffic, where the cyclist may feel the need to stop suddenly, to jump off the bicycle, or lift it suddenly onto a curb, in response to an impending hazard. The ability to perform agile body motions without the feet being attached to the pedals is the main reason why cyclists performing the sport of observed trials cycling (a form of obstacle course riding over difficult terrain), BMX (bicycle motocross racing) or freestyle (stunt riding at low speed on ramps and found urban objects) bicycle riding typically use unbound style pedals. This is true even though clipless binding pedals might appear to give the cyclist an advantage in hopping the bicycle over obstacles, as is often done in these sports. When encountering difficult terrain, the cyclist using clipless pedals cannot easily lift a foot off the pedal to maintain balance, and thus must often dismount the bicycle to walk it through, whereas they might be able to ride through it if they had unbound style pedals installed. Few cyclists, if any, carry an extra set of pedals and a wrench to change them, when they ride, as these items are heavy, and it is difficult and time consuming to perform this operation.
One manufacturer, Shimano, makes a pedal, model number M-323, which has a clipless binding on one side and a cage on the other side, the cage intended for unbound use only, and not for use with a toeclip and toestrap. This pedal has the advantage that the cyclist may comfortably ride the bicycle regardless of the type of shoe being worn. In addition, the cyclist wearing a shoe with a recessed cleat designed to engage the clipless binding, may ride in either unbound mode or clipped in mode. However, when mounting the pedal, either on the clipless binding side, or on the cage side, the cyclist must still look and/or feel for the side desired, and then spin the pedal one half turn, if necessary, to turn the desired side up. As with the aforementioned toeclip type and single sided clipless binding type pedals, this operation requires practice and concentration to perform smoothly and proficiently, and thus this pedal suffers many of the aforementioned disadvantages of both toeclip type and clipless binding type pedals. In most of the aforementioned situations where clipless and toeclip type pedals are difficult to mount and clip into, the operation of looking and/or feeling for which side is up, then spinning the pedal one half turn to place the cage side up is only marginally less difficult, due to the high probability of overspinning the pedal under the time pressure of mounting the bike and quickly clipping in. In addition, when riding in either mode, the cyclist must perform this operation every time he/she takes their foot off the pedal, as the pedal may spin to place the opposite, undesired side upwards. This problem is most pronounced when riding in unbound style, as the foot comes off the pedal easier, and more frequently. As such this pedal is at a disadvantage compared to conventional unbound type pedals for riding in difficult terrain or in conditions where the cyclist desires to ride in unbound mode while maintaining the ability to lift the foot off the pedal freely.
Nagano, U.S. Pat. No. 5,806,379 (1998) shows a bicycle pedal system having both clipless bindings and unbound type tread surfaces. The preferred embodiment is essentially a clipless binding pedal supplied with separate platform type tread surfaces that attach to the binding using an integrally formed cleat on the underside of the platform surface. This is an obvious solution for providing dual mode clipless or unbound capability on either one or both sides of the pedal. It is difficult to install and remove because the typical cleat engagement force of the binding is necessarily high, to prevent inadvertent cleat release from sideways foot pressure under the full weight of the rider. The tread surfaces must be installed by hand and thus great hand pressure is required to install and remove them, typically beyond the capability of most riders. A lever tool, such as a screwdriver must often be used to remove these platforms from the bindings. An alternative embodiment shows an unbound type pedal, similar to a platform or cage style pedal, that allows the attachment of clipless binding mechanisms, using screw fasteners. This alternative is also difficult to use, by the obvious requirement to separately carry a screwdriver. Both embodiments require the user to separately carry the platform surface or clipless binding attachments plus any tools needed to install them, a clear drawback. Both embodiments also require the user to stop riding in order to attach or detach the platform surface attachments, another clear drawback.
Chen, U.S. Pat. No. 5,916,332 (1999) shows a cage type pedal having a detachable clipless binding for a recessed type cleat mounted on one side of the pedal. This pedal has the advantage of being convertible to unbound mode on both sides of the pedal by removing the clipless binding, which is attached to the pedal with a screw. This pedal, however, has the same disadvantages of the pedal system of Nagano, U.S. Pat. No. 5,806,379 by requiring the rider to stop and dismount the bicycle in order change pedal operation modes, and by requiring the rider to carry either a screwdriver or hex wrench, and to carry the separate clipless binding when operating in unbound mode on both sides of the pedal.
What is needed is a clipless pedal for a recessed type cleat, that can be set or configured to operate as either a unbound pedal on both sides of the pedal, or as a clipless pedal on both sides of the pedal, so that the cyclist does not have to carry separate platform attachments, bindings, screwdrivers, hex wrenches, or other tools in order to change operation modes. Such a pedal would not require the cyclist to determine which side is up when mounting the pedals, and would allow him/her to simply step on the pedals (clipping in to the binding, if using clipless binding mode), and commence pedaling immediately. Furthermore, the mode of operation should be easily and quickly changeable without the need for the cyclist to stop, or even to look down at the pedals while coasting. Another benefit would be that the same set of pedals providing recessed cleat clipless operation would also allow comfortable cycling with any kind of shoe suitable for unbound operation, without the necessity of spinning the pedal to select the desired mode of pedal use. Such a convertible, truly dual mode pedal would eliminate the need to have more than one set of pedals, frequently installing and removing them from the crank arms, a process that eventually damages the pedal threads on the crankarm, or to carry separate platform surfaces or bindings.
There are some recent pedal designs which attempt to provide both unbound and clipless operation on both sides of the pedal, with only limited success. Hanamura, U.S. Pat. No. 5,771,757 (1998) shows a pedal which incorporates clipless bindings on both sides of a pedal body having a large shoe contacting area, with similarities to a cage style pedal, surrounding both clipless bindings. The clipless bindings, however, protrude above the shoe contacting area of the cage at all times. This protrusion of the binding above the shoe supporting surface is necessary to properly engage the shoe cleat that is recessed into the shoe sole. This pedal is designed primarily for off-road downhill use, where the cyclist is usually clipped in, but becomes unexpectedly unclipped and cannot immediately clip back in due to travel at high speeds on rough terrain. Under these circumstances it is helpful to have cages surrounding the bindings to assist the cyclist in locating the pedal, providing a temporary place for the shoe to rest until the cyclist can get clipped back in. Limited propulsive pedaling may be possible without clipping back in, but the clipless binding which protrudes above the shoe supporting surface is slippery against the cleat when not properly engaged. The rider is forced to place his/her foot substantially askew in order to gain a secure foot placement. In addition, the bindings protruding above the shoe supporting surfaces are also slippery and uncomfortable against non cycling shoes without a cleat. Most non-cycling shoes have a relatively compliant sole and the foot feels a concentrated pressure under the small clipless binding. Thus, this pedal does not allow comfortable, safe, or efficient pedaling with any shoe which is not clipped in to the binding; as such, it is not suitable for unbound style riding, except under the temporary and specific conditions it was designed for.
Ueda, U.S. Pat. No. 5,784,931 (1998) shows a clipless bicycle pedal designed to engage a recessed cleat, having a spring loaded, rotatable tread cage surrounding the clipless binding. This design is a variation of the previous design of Hanamura, U.S. Pat. No. 5,771,757, in attempting to provide contact between the tread cage and the shoe sole while the cleat is engaged with the binding mechanism. It is described, though not claimed, as providing a shoe resting surface for a cycling shoe when the cleat cannot be engaged, as encountered during many types of off-road bicycle racing. No figure shows a shoe sole being supported by the cage alone. Under any significant foot pressure, the tread cage will rotate relative to the binding with the result being that the cleat engaging members of the binding protrude substantially above the top of the tread cage. Thus the shoe is supported either on top of, or engaged with the binding. If the shoe is placed on the pedal with the ball of the foot over the pedal spindle axis, only a cleat engaged position will be stable, for if the cleat is not properly engaged with the binding, there is only metal to metal contact between the bottom of the cleat and the top of the binding which is very slippery and insecure. If the shoe is placed on the pedal in a substantially different orientation, so as to avoid contact of the cleat with the binding, then the top surface of the binding contacts the sole of the shoe. Thus, the shoe is supported primarily by the top of the binding, instead of the shoe cage. This is again, a slippery and insecure form of support. Furthermore, this foot position does not allow safe, secure comfortable or and efficient pedaling. In order to have contact between the sole of the shoe and the top of the tread cage, the shoe must be at least substantially tilted to one side or the other, which is again is not safe, secure, comfortable or efficient for pedalling. As such, the cage is not significantly supportive of the rider's foot and cannot provide a stable shoe supporting surface for any type of shoe. As such this pedal cannot be considered a dual mode unbound/clipless pedal; it is a clipless pedal that attempts to provide a temporary surface for the rider to place their foot when terrain and/or speed prevent them from immediately clipping in to the binding. Thus this pedal design is not effective for use in unbound mode, and, like the design of Nagano, U.S. Pat. No. 5,771,757 described above, is intended only to aid the rider in achieving cleat engagement under difficult circumstances. As such, it does not anticipate a bicycle pedal according to this invention, as it does not provide sufficient height variability between a binding and a shoe supporting surface to be comfortably and safely usable in either clipless or unbound mode.
Other pedal designs show height variability between a clipless binding and the pedal body, though not for the purpose of providing both unbound and clipless modes on a single pedal. Ueda, U.S. Pat. No. 6,012,356 (2000) shows a clipless bicycle pedal designed for a flush or recessed shoe cleat having a small amount of height variability between the binding and the pedal body, for the purpose of achieving a slight amount of contact between the portion of the shoe sole laterally surrounding the cleat and the pedal body. This lateral shoe sole contact is claimed to reduce side to side rocking of the shoe when engaged with the cleat. This pedal is designed for clipless operation only, and the pedal body is formed to directly support the shoe sole only at two small areas over the pedal spindle; it does not provide unbound style support over a large shoe sole area. The small amount of height variability acts only on part of the binding and would not be sufficient to fully retract the binding into an platform or cage style pedal body to allow it to be used in an unbound mode.
A desirable modification to the aforementioned desired dual mode clipless/unbound pedal having a choice of either clipless or unbound operation on both pedal sides, which would be useful for riding in steep or difficult terrain, or for riding in busy traffic, would be for the cyclist to be able to preset the pedal to automatically transform to an unbound type pedal on both sides of the pedal, immediately upon the release of the cleat from the binding. This would allow a cyclist wearing cycling shoes with recessed clipless binding cleats to deliberately unclip from the pedal and continue pedaling, uninterrupted, in unbound mode over sections of difficult terrain, or in busy traffic for instance, without having to first unclip, and then reach down to convert the pedal to unbound mode. The conversion operation could be difficult or impossible to perform while coasting the bicycle in these conditions, requiring the rider to stop to make the conversion. This automatic conversion feature thus allows a cyclist to remain riding clipped in, as long as possible, as it eliminates the necessity of predetermining or guessing where the terrain or riding conditions become too difficult to continue riding while being clipped in. Thus, a cyclist could ride while staying clipped in into more difficult terrain than otherwise possible, as the rider would not have to stop to switch the pedals to unbound mode. This would be a decided advantage in off road competitive riding on difficult terrain.
Another useful pedal design for certain types of riding such as observed trials or freestyle, would be a pedal which features a fixed height shoe supporting surface on one side, in combination with a clipless binding and shoe supporting surface on the other side, where the relative height between the binding and shoe supporting surface (on the same side) are sufficiently variable to allow the pedal to be used as an unbound style pedal on both sides, or as an unbound pedal on one side, and a clipless pedal on the other side. This would allow the cyclist to use the downward facing surface to momentarily rest or balance on a log, rock, curb, or other suitable object, as is done in above mentioned sports, while remaining clipped in. The downward facing shoe supporting surface would provide better grip on objects, and be less susceptible to damage than an exposed binding facing downwards. A desirable modification of this design would be to additionally be able to set the pedal to automatically transform to an unbound type pedal on both sides of the pedal, immediately upon the release of the cleat from the binding, as described in the preceding paragraph. Thus, the cyclist can ensure that a shoe supporting surface always faces downward, even after unclipping from the pedal.